Double acting electrohydraulic operator



Aug. 14,A 1934. w. .Lf wooDs DOUBLE ACTING-ELEC'ROHYDRAULIC OPERATOR Filed Oct. 2, 1930 William J. Woods, b5 (4M I-I's Atborneg .530; of ipneumaticall-y `operated `devicesfsuch as lliiuid Patented Aug. 14, 1934 rara-Nr carica ponete .ACTING ELEcaa-onrnnnmo @Pasaron 'William J. Woods, Schenectady;N."Y.,.assignor"to.

Gen-eralElectricCmpany, 'a

York

coi-poration'o'fNew apprenne october 2, 19sser'ia1.No.As5,952

122 fClaims.

'My invention relates to felectrofhydraulic Aioperating devices, :and :provides an :improved v:form o'i .double acting 'or ,reversible electro-hydraulic operating device gior producing a sreciprocating motion which Amay :readily .beadapted for a Wide el'cl .of vservice but is particularly advantageous for opening and closing @elevator doors.

vIn Iitlie :systems Y-now generally 'provided for opening :and closing elevator cdoors, use ,is .made

operated cylinders or .ci electric 'motor driven lever :mechanisms Acarried "the :elevator cab proper and which engage the .door to operate it. In'th'epneumatic systems making 4.use of pis- "1 tons 'andilever mechanism for openingand closing .elevator :doorsit is necessaryto provide some form lor" compressor usually vlocated in 'the basement cof v.the ibuilding :in 'which :the elevator lsystem :is installed. Conduits `are lledifromtlie 4compressor :system .and tap 'off at 'the various floors to the pneumatic pistons and valves Whichxcontrol the 'levermechanisrn for openingizhe-idoors. Such :a Asystem trequires an lelaborate `layout and constant :attention to imaintain the systeml :in operative condition. 4The controlvalves, ,thepiston's and also 'the l.conduit )leading the 'compressed u'id Vto the pistons .are :all :subject to leaks xyvliicli may :cause :a `,dangerous 'condition requiringsuspension :of the #elevator 4,service `and lexpensive c repairs.

In fthe fsecon'd 'type of :mechanism used -for opening the doors tlie'rotary :motion of the electric driving :motor must he converted finto linear moti-on by :means foi elaborate Yand `complicated ratchet and lever .fmechanis`m- `llurtliermore speedreductionzgearingtis necessaryzto reducethe speedo the :driving motor so thatfit'can beiused for opening and closing the doors. Limit switches also .arefnecessary to limit Ltliemovernent .fof the doors :and overload protective .systems are required to 1.insure :safe operation. in ,the felect-ric motor type of elevator 'door closing :and fopening apparatus theientire apparatusgincluding the re.- duction gearing, 'limit sswitches, and overload fdevices are `carried iloy the fcao proper 4thus :adding prevent closing of the .door with Ia slam. This safety door .check vmechf/inisrn is ,usually aexpensive and -is subject 'to `manyof the-.same `olofjections as the pnuematicallyoperated .mechanism for opening and fclosing ltlfle door.

It has been vfound that in rboth .these systems accidents occur by having passengers :caught between the l:doorsfas tlredoorsare closing. In both systems ithe ipneumatically @operated [type and 'in the electric motor :type when .some tob- `iect is icaught betvveen the :doors the pressure exerted iby ithe closing -.doors' increases 1aintil :the pneumatic system 'or theimotor .system b'ecomes overloaded "at 4.vvloich '.time :some :overload tripping device usually :deenergizes the rclos'ing 'mechanism. However, 'zbefore the tripping .'device voperates :serious iirrjuny may ibe done tto ithe :passenger.

Hence, :it is :one rdf 'the `:principal objects :of .'my invention :to iprovide .fa @reversible felectro-ihydraulic operator fior :opening land closing veleva-- tor :doors `.Which-is afself-:ccntained unit of relativelyfsmallssizefand aweightfand of :as .simple u and trouble-'free [construction :as possible.

sIt iis fan :object roi '.my .iinvention to iprovide 1an electro-hydraulic :operator'i'of 'the 'above Ftype which eliminates the necessity for limit switches, overload protection, .safety door icliecks, :compressor :apparatus :and auxiliary fpipes, fand oy means fof which ithe .safety of the passengers fis assured. i

3It iis fa 'further :object fof r-.my 'iinventi'on ito ipro-v vide an electroshydraulic operatormaking'use of a :reversible :electric z'motor itogether with ia "double "impeller 'ui'd pressure :creating 'means and a reciprocating `.piston mechanism ffcr `imparting movemeritin opposite directionstoarwoklengaging member.

.-Briey, 'thejpreferred :embodiment `lof my -invention fc'onsists of :a :fluid casing :provided with a -.central .oilofeservoir 1in which =is mounted -a double impeller :reversible :pump of uniquesstructure, land ihaving la rpair of oppositely :disposed cylinders .connectedto the central ireservoir by communicating passagesjopening linto the .interior `of .the reservoir. The double ximpeller re- Versihle pump ,-is (connected .by `means of .a rdrive shaft `to ia reversible .electric .motor ,mounted `upon the -.central.r.eser.voir. .Slidably-mounted upon ran oil tube ,guide .in `each cylinder is a .reciprocating piston, ltheltvo ,-pistonsbeing migidlyiastened togather .by meansof .a ,pair of'lconnec'ting rods. These -.connecting .rods .are .connected by means of arrank .mechanism .extending through .the casingahove the .level .of .the \oil .Within .the reservoir .-to apiyotally mounted Work .engaging membei' operating outside lof .the casing. l,Ihis :form of crank `connection eliminates .the necessityffor packing Ato fprevent'leakage of .oil-from the .pistons if `the.connecting rods .orother Workingparts extended through V.the .casing Jbelow .the `oil level.A

Passageways are provided between the reservoir and the cylinders so that when the impeller pump is rotated in one direction or the other the pistons will move in response to the pressure created in the fluid in a direction corresponding to the direction of rotation of the double operating impeller pump. Inv this way selective operation of the work engaging member by a substantially constant fluid pressure or force in either direc-V tion may be obtained.

A more complete understanding of my invention will be obtained by reference to the accompanying drawing in which Fig. 1 shows a partial cross sectional view of a preferred form of my device; Fig. 2 a cross section taken rthrough Fig. 1 as indicated by the sectional line A, A; Fig. 3 is a partial sectional view taken looking down upon the top of the device as shown in Fig. 1. Fig. 4 is a detailed showing of the'clutch mechanism employed to effect selective actuation of the two impellers.

Referring specifically to the drawing, the uid casing comprisesl the central reservoir 10 and the cylinders l1 and 12-fastened thereto at opposite sides thereof by means of suitable screws. The interior of the reservoir is filled with oilabove the level of the cylinders as indicated by the dotted line in Fig. 1. The interior of the reservoir is provided with semi-circular portions 13 and 14 and with the chambers 43 and 44 in which the crank mechanism and members connecting the piston rods thereto may move.

Mounted in the bottom of the reservoir section of the casing is the impeller pump housing consisting of the portions`15.' 15 and 16. The portions 13 and 14 are extended around to enclose the parts of the pumphousing as shown at 13` 17' and 18 to which the impeller blades are attached.

The mounting of the impellers upon the drive shaft 21 isrshown in detail in Fig. 4. The impeller hubs 17 and 18 are provided with ratchet 1 toothed indentations such as 171 and 181, which permit positive drivingengagement in one direction only. Cooperatingr therewith are the clutching elements 271 and 27 provided with the toothed portions v28 and 28' -which cooperate with the toothed indentations of the hubs; these elements being slidably keyed to the shaft 21 by means of the key 21 and urged into contact with the hub members by means ofthe spring 27. When the motor rotates the impeller shaft in one direction, let us say for example with a left-hand rotation, the clutching element 271 will engage one of the toothed indentations, such as 171, vin the hub 17 and positively drive the same. Due to the inertia of the impeller hub 18 and the oil between the impeller blades and to the' fact that the other clutching element can slip with respect tothe toothed indentations in the hub 18 the clutching member 27 will merely slip over the 'teeth with- A out rotating the impeller. When therotation of the driving motor 22 is reversed the opposite ac-v tion takesplace, the impeller 18 being positivelyI driven while the clutching member 271 will kslip with respect to theimpeller 17. 'Ihe spring of course is so adjusted that thejforce exerted thereby upon the slipping clutching member is bal. anced by the force exerted by the inertia of the impeller and oil upon the clutching member to force it out of lengagement with the impeller proper therebypermitting relative slipping between the drive shaft and the impeller.

The purpose of this construction is to permit a positive drive of each impeller in one direction only, the direction being opposite for each so that when the electric driving motor 22 is energized to rotate in either direction only one of the impellers will be rotated at a time. These impellers are driven by means of a drive shaft 21 connected between the impellers and the motor 22. Keyed to the shaft 21 is the fan 23 which tends to cool the motor and motor bearings during operation. The pistons 29 and 30 are mounted within the cylinders 11 and 12 and slide on the oil tube guides 31 and 32 the pistons being rigidly fastened together by means of the connecting rods 35 and 36 so that during operation both pistons move together. The oil tube guides 31 and 32 are provided with the openings 33 and 34 respectively to permit the passage of oil to and from one side of the piston to the interior of the oil reservoir through the oil tubes and the openings 31 and 32 in the oil reservoir portion of the casing.

The housing for the impellers is provided with the exhaust openings 19 and 2O for connecting the interior of the cylinders 11 and 12 with the impeller pumps so that when the impeller 17 is energized oil will be forced through the opening 19 to one side of piston 29 in the cylinder 11 thus moving the pistons to the left, and similarly when the impeller pump 18 is energized oil will be forced 105 through the passage 20 to the interior or the cylinder l2 to one side of piston 30 moving the pistons to the right.

Oil is introduced to both sides of the impellers during operation, at the top through the opening 26 in the impeller pump housing and at the bottom through the chamber 25 connected to the oil reservoir by chambers 43 and 414, and opening 25', the oil passing by the blades of the impeller which happens to be stationary during the operation of 115 the other.

When oil is forced through the opening 19 into the cylinder 11 the piston 29 moves to the left and forces the oil on the left hand side thereof through the openings 33 of oil tube guide 31, 12o through the oil tube guide and the opening 31 to the interior of the reservoir 10. Similarly, when oil is forced through the passage 20 to one side of piston 30 oil will be forced from the right hand side ofthe piston 30 through the openings 34 125 and through the oil tube 32 to the interior of the oil reservoir through opening 32.

The chamber 25 connects with the upper side of the impeller pump housing around the housing by means of the chambers 43 and 44 provided for 330 the crank mechanism and which open up into the Voil reservoir. This can be clearly seen in Fig. 2.

A work engaging member 42 is pivotally mounted on the outside of the casing and is connected 135 to the connecting rods 35 and 36 by means of a crank mechanism consisting of the stub shafts 431 and 41, and crank arms 39 and 40 which are. pivotally connected to the blocks 37 and 38 rigidly fastened to the connecting rods 35 and 36. The crank members 39 and 40 are provided with elongated slots such as 39 (see Fig. l) in order to permit free sliding and pivotal movement of the cranks during their reciprocating motion. Thus as'the pistons move in opposite directions 145 the motion thereof is transmitted through crank mechanism to the work engaging member producing a'reciprocating motion thereof.

rlhe particular method employed in transmit- A l ting the motion of the pistons to the workv engag- L50 ipsum?? ing'rmember 142 Lbyameans :oi :the stub A01 and sil :mountediin'hearings ialiove oil level is important. This eliminates the necessity iiur paekings to zprfevent oil leakage, which pachings areV aconstantly :a .source .of 'worry rand :trouble Elurther, this .particular .crank fconnection mesults inv ra avery .compact unit, which -zcould not be acirtained :by .extending ttheaconnecting rods through the :cylinders in line with 'the pistons.

l l'.'Jl'he operation of:theidevicelis'asfollovzs: When the mater 522 iis energized to )rotaie ,the :impoller le .'lgynneans:of springimtged Lclutchingfmechanism :nil tro-m thief-oil :reservoir il() ireachesiiihe `.top portion nf theiimpe'ller through lthe ripening 25 pastttheiimpelier .L17 avhich iseslippingwith-respect tofdrive shaft 2l. .@il :reaches ithe iundersidefof the mpellerefromzthe oil resem/:oir di) through .the chambers 1.43 and 44 '.to the chamber Vand thrnugh tlie .opening 25'.. The oil iis ieapelled thereiromithronghithe passagelZi) totheleftf'hand side of iihexpistonl thereby causing apressure to be a'exerted therecn :to :move the :piston to fthe right. siitidoessso it :iorcesthe :oil ,on ithefrighthand sidethere'of through fthe opening-s .3d :of the oil tube guide :32,the oilitubefandack itc-:the oil :reservoir through the `:opening 1,32 1in fthe oil reservoir gli). Piston 129 sheing connecte-d itol `the piston 13D 'of :course movies [to :the right-.With it :and ierces .the1oilon the :right-hand f'side :of fthe ipiston 'through the :opening .19 te the atop portion of the '.'impeller .18 andto fthe :reservoir proper. Oil reaches the left-lhand side -`oi 'the piston through fthe fopening 31' iin 'ithe f oil reservoir, oil

tube :l-1 andtthrough .fthe openings 33 therein.

JA freverse'action 7takes :place when V,the ymotor '22 isireverseditotpositively drivethe impeller ,17,the oil ,entering (the top `portionand lower aporticn rof the zimpeller `17 :as describedfor ithe impeller r'Eheitoeth .v2.8 is znovv forcediintocengagement the teethfon thelhulo I7' to-cause:a:positivedrive, While fthe ttoothxwhichaengages the hub i8 :oi `lthe impeller 18 merely slips :past the teeth Without causing `motion `of the zimpeller. v'Oil is 'forced through opening 179 :againstpiston 29 ntoemoveithe pistonsito! f thejeft. @femm-se, .thezmotionfof the pistons is transmitted through the crank mechanism it'o .the `vvorls engaging meniher -42 and l:by intermittently .reversing them'otor 22 a 'reciproeating zmotionsof the wor-k aengag'ing lmemberfmay ,I be obtained.

' :Since -the .motion of the 'pistons Fwithin the cylinders iis .slow *enough fior fthe `.purpose to rbe served :no :reduction ygearing iis necessary between the electricin'iotor '22 and the 'impeller rpump. kNo

overload :or limit switches are necessary `in the construction given 'above ibecause when the pistons reach either 'limit Zthe ,impeller .pump .-*merely spins in 'the -oil Without .causing 'any further movement :of the Work Yengagingfmemherror :overloading fthe motor. -VSince lan :electric .driving motor is lused 4electrical control is fpossible.

'It Willthus be seen .that with my 4construction I obtain "the A.ease of electrical -ccntrol 'which Aislso highly desirable. 'By means "of lrny unique .construction vI eliminate 'the necessity A'for :using -reduction gearing 'between fthe `motor and .the member to be operated on, the complicated :gear and aratchet mechanism fior obtaining linear @motion from rotational movement, and ylimit and A -1 overload .devices 'since `these problems do .not

present fthemse'lves'by the `.use of lm37-'construction- The embodiment of *the `invention iillustrated and described herein has Vbeen `selected Ifor .fthe

purpose :of fclearlysetting forth Ithe `principles 'l involved. twill be'apparentfhowelver, that the invention lis susceptible auf :being lrriodied tofmeet the .different iconditions fermountered in ruse, and 5I, :therefore :aim atoifcover by zthe appended claims .all :of ithe modifications 'within theftrue spirit sandrscope of imyfinvention.

. .xWhatzI claim as new and :desire zto :secure .by Iietters iRatent of the United #States sis:-

1. An electro-hydraulic aoperator :including :a iiuid casing, aiplur'al'rtyroflimpeller ipumps in said casing, ier reating .different tfluid pressures A'in ,tire uid, ;a=pistonrmeans'movable in copposite direutions :in .response-ato 'the fdierent fluid ,pres- .in Lthe ',fflui'd 1in :said ceasing, fluid connecting means fhetiveensaid pumps .and fpistonA meansand electric driving :nreans'fior selectively operating said ipumps to cause lmovement ofssaid piston means :in opposite .directions a A hydraulic @operator ,iincluding a :fluid casing,.'a1pair' .of pistonsimmersedin :thezluid there in, ',apressurefcreating :device-in saidfcasing .comprisingra pair ofzimpelleripumpsfcr moving said pistons, :uid connecting .means '-.betvveen said pumps :and said fpistons, and l'driving `means Vfor selectively' driving lsaid pumps `:in eopposite fdirections to create diierentrpressures'iinisaidiluid tp :move-.saidpistons alternately :in `.opugzositefdirections. J

3. An electroJhydraulic operator .including :an operating .member .movable .each "Way :between two positions, 5 a .reversiltile' :electric driving .meten and duid-pressure means-operatively connecting themotor Withlthe member-'andhavingfa pressure creating impeller 4connected to :be :driven .by the motor fto effect ioperation f. of :said `:member ;to ione of f-said ipos'iti'ons upon' operation of the imotor ;in one direction and a .se-cond pressure creating zimpeller connected to be :driven Iby Ithe unotor fto effect opera-tion' of said'member 'to 1the tether :of said ipositions'upon :operation of fthezmotor tin the reverse direction.

f f4. A Thydraulic operator :including -a iiiid `rasing, a=pair1df oppositely disposedrpistons'mounted for :simultaneous movement .Within the ffluid Ain said casing, ya "pair of impeller pumps .immersed inthe fluid in saidcasing forcreatinga pressure to Imove lsaid pistons, A,a :reversible jdriving means therefor, .and 1a selective :clutch mechanism ibetween said fdriving :means and said pumps, said pumps ibe'ing driven in A'opposite directions -it'otpro duce a reciprocating ymovement Lof said ,pistons and a Work engaging member operatively `con-- nected to said fpistons tobe moved thereby .'in

response to 'theiope'rationloi said 'impeller apumps.

f 5. /A hydraulicoperator includingfaifluidrcasing comprisinga central fluid :reservoir and oppositely `'disposed fluid :cylinders Shavingfconnecting conduits to said reservoir, pistons=mounted .in :said cylinders, and=connecting .rodsrigidly Aconnecting said pistons itc each vother to lcause .simultaneous movement thereof, fa i'plurality Y. of :pressure fcreating impelle'r pumps each adapted tolbeidriven inv an oppositedirection, a -fluid'fconnection between the vdischarge of #each pump .and one iside .of fa diiierent piston, a driving means for .selectively operating said impellers .whereby `a 'pressure is alternately `.exerted upon :each of .said pistons Cto move 'the pistons .alternately lin opposite :directions,.andaa Work engaging lever mounted `on the outside of saidc'asingtand means-:connecting said connectingrodsfand lever.

f6.' A hydraulic operator ,including .a l:lu'id casing, a .pair 'of loppositely disposed pistons iconnected f'together and mounted for movement Within fthe fluid .in saidv casing, faipressure :creating device 'comprising .a :pair tof impeller pumps im-l 'ses mersed in the fluid for applying a pressure against said pistons, a driving means for selectively operating said pumps to move said pistons alternately in `opposite directions, and a work engaging member ope-ratively connected to said pistons whereby a reciprocating movement of said work engaging member is produced when said pumps are selectively operated.

'7. A hydraulic operator including a fluid casing, a pair of oppositely disposed pistons mounted for movement within the iiuid in said casing, means for rigidly connecting said pistons toeach other to produce simultaneous movement thereof, a, pressure creating device immersed in said fluid comprising a pair of pumps for selectively applying a pressure against said pistons to move the same alternately in opposite directions, a reversible driving means for said pressure creating device, connecting means between said driving means and rsaidpumps for selectively operating said pumps, and a work engaging member operatively connected to said pistons whereby a reciprocating movement of said work engaging member is' produced when said pressure creating means is selectively operated.

8. An electro-hydraulic operator including a fluid casing, a pair of pistons mounted for limited simultaneous movement within the casing, a pressure creating device for each of said pistons within said casing and a reversible electric motor for causing selective operation of said pressure creating devices for moving said pistons'alternately in opposite directions, said pistons being balanced to remain at the limits of movement when the operating motor of said pressure creating means is deenergized.

9. An electro-hydraulic operator including a fluid casing, oppositely disposed pressure .responsive means within said casing adapted to have a limited reciprocating movement in the iiuid in said casing, a reversible pressure creating means in said casing comprising a pair of impeller pumps for alternately creating a pressure against said pressure responsive means for causing reciprocating movement ,of said pressure responsive means, and electric driving means therefor for selectively operating said pumps to cause said reciprocating movement, said pressure responsive means being balanced to remain at the limits of movement when said driving means is deenergized.

10. A hydraulic operator including a pair of cylinders, pistons in said-cylinders connected to move together, a fluid reservoir, pressure creating means in said reservoir for moving said pistons and provided with intake and exhaust means, driving means for said pressure creating means, the exhaust means of said pressure creating means opening into the cylinders on one side of said pistons and conduits connecting the other side of said pistons and said reservoir, said conduits permitting a balance of pressure on opposite sides of said pistons when said driving means is deenergized.

11. A hydraulic operatorincluding a pair of cylinders, pistons in said cylinders connected to move together, a fluid reservoir, pressure creating means in said reservoir for moving said pistons and provided with intake and exhaust means, driving means for said pressure creating means, the exhaust means of said pressure creating means opening into said cylinders on one side of said pistons and conduits extending through said pistons for connecting the other side of said pistons and said reservoir, said conduits permitting a balance of pressure on opposite sides of said pistons when said driving means is deenergized.

12. A hydraulic operator for obtaining a reciprocating movement, including a fluid casing, said casing being provided with a fluid reservoir and oppositely disposed cylinders at right angles thereto, fluid tubes connecting said reservoir and the interior of said cylinders and providing passages thereto for uid, pistons slidable on said tubes within said cylinders, rods rigidly connecting said pistons for causing simultaneous movement thereof, a pair of impeller pumps mounted in said casing, each impeller pump having an exhaust connected to one of said cylinders to create a fluid pressure therein to move the piston, driving means for said impellers, one only of said impellers being operative at a time whereby a reciprocating movement of said pistons may be obtained by alternate operation of said impellers, said tubes and exhausts providing passages for fluid to and from opposite sides of said pistons and a work engaging lever mounted upon the outside of said casing and operatively connected to said work engaging member.

13. A hydraulic operator including a fluid casing, a uid therein, a pair of oppositely disposed pistons mounted within said casing for horizontal movement within the fluid, connecting rods rigidly connecting said pistons to cause simultaneously movement thereof, a pressure creating device immersed in the fluid intermediate said pistons for selectively operating said pistons to move them alternately in opposite directions, a driving means for said pressure creating means, a movable work engaging member mounted without said casing, blocks mounted upon said connecting rods for movement therewith, cranks pivotally connected to said blocks and extending through the casing above the level of the fluid therein, said work engaging member being connected to said cranks whereby upon movement of said pistons in response to operation of said pressure creating means a reciprocating movement of said work engaging member is obtained.

14. A hydraulic operator including a fluid casing, a pair of oppositely disposed pistons mounted for horizontal movement within the fluid in said casing, pumps immersed in the fluid for selectively applying a pressure to said pistons 'to move the same alternately in opposite directions, a driving means for selectively operating said pumps, connecting rods for connecting said pistons together to cause'simultaneous movement thereof,` blocks mounted upon Ysaid connecting rods for movement therewith, cranks slidably and pivotally connected to said blocks, bearings in said casing, stub shafts rotatably supported thereby, said cranks being connected to said stub shafts, a work engaging member mounted without said casing and keyedto said stub shafts whereby upon movement of said pistons alternately in opposite directions a reciprocating movement will be transmitted through said cranks and shafts to said work engaging, member, said bearings for said stub shafts being mounted above the level ofthe fluid within said casing to prevent the leakage of uid therefrom. f

15. A hydraulic operator forobtaining a reciprocating movement including a fluid casing, pistons within said casing, connecting rods rigidly connecting said pistons for causing simultaneous movement thereof, means mounted in said casing for Vcreating a fluid pressure in said casing to move said pistons, driving means for said pressure creating means, blocks mounted upon said co-nnecting rods to move therewith, cranks slidably and pivotally connected to said blocks, vbearings in said casing above the fluid level therein, stub shafts extending through said casing and rotatable in said bearings, a work engaging member mounted for movement with respect t-o said casing, said cranks and said work engaging member being operatively connected through said casing by means of said stub shafts, said block, crank and shaft connections between said connecting rods and said work engaging member transmit-Y ting movement of said pistons to said Work engaging member when said pressure creating means is energized.

16. An electro-hydraulic operator for providing a reciprocating movement comprising a fluid reservoir, a pump housing and a pair of impeller pumps located therein for providing a fluid pressure, a plurality of cylinders disposed on opposite sides of said iluid reservoir, pistons slidably mounted therein and adapted to be -operated by said pumps, connecting rods for connecting said pistons together to cause simultaneous movement thereof, passageways between said cylinders and said pump housing and said fluid reservoir and pump housing to permit the passage of fluid to and from said pumps when said pumps are operated t-o move said pistons, a reversible electric driving motor for rotating said impeller pumps, a spring actuated clutch mechanism between said impeller pumps and said electric driving motor for selectively' rotating each impeller pump in an opposite direction upon reversal of said motor, whereby a reciprocating movement of said pistons will be obtained, and a work engaging member operatively connected to said pistons for transmitting said reciprocating movement.

1'7. An electro-hydraulic operator for providing a reciprocating movement including a casing having a central fluid reservoir and provided with cylinders oppositely disposed at-right angles to said reservoir, fluid tube guides centrally disposed in said cylinders and provided with openings therein for providing a passage for fluid to and from the fluid reservoir and said cylinders, pistons slidably mounted on said tubes within said cylinders and rigidly connected together by connecting rods for causing simultaneous movement of said pistons, said tubes opening intosaid cylinders on one side of said pistons, a pump housing mounted in said fluid reservoirV at the bottom thereof provided with intake and exhaust passages, said exhaust passage opening into said cylinders on the other side of said pistonsa pair of impeller pumps mounted for rotation within said housing for creating a pressure in said fluid for moving said pistons, electric driving means for said impellers, said driving means being adapted to have a selective operating engagement with said impeller pumps for rotating each pump in an opposite direction whereby a fluid pressure will be alternately created thereby on one side of each piston to move said pistons alternately in opposite directions, a work engaging lever mounted without said casing for pivotal movement and a crank mechanism extending through the casing above the level of the fluid for operatively connecting said pistons and said work engaging member for causing a reciprocating movement thereof.

18. An electro-hydraulic motor, comprising a double-acting hydraulic motor, a double acting reciprocating piston therein, rotary impeller pump means for supplying liquid under pressure Y for driving said double-acting piston, an electric motor driving said pump means, a rock-shaft for applying the force developed upon said piston, driving connections to said rock shaft from a part of said double-acting piston intermediate its ends, and a common housing for said pump means and double-acting piston, said rock shaft passing through said common housing above the liquid level in said housing.

19. An electro-hydraulic motorv comprising a double-acting hydraulic motor having a doubleacting cylinder and a double-acting piston therein, a pump incorporated with said hydraulic motor and located intermediate the ends of said double-acting cylinder, said pump comprising a rotary impeller for supplying liquid under pressure for driving said double-acting piston, and an electric motor driving said impeller, said electric motor having a shaft passing through said piston intermediate its ends and connected with said impeller.

20. An electro-hydraulic motor comprising a double-acting hydraulic motor having a doubleacting cylinder and a double-acting piston therein, a pump incorporated with said hydraulic motor and located intermediate the ends of said double-acting cylinder, said pump comprising a rotary impeller for supplying liquid under pressure for driving said double-acting piston, said double-acting piston having a thrust-bar intermediate its ends, a rock-shaft for applying the force developed upon said piston, driving connections between said rock-shaft and thrust-bar, and an electric motor driving said impeller, said electric motor having a shaft passing through said piston intermediate its ends and connected with said impeller.

2.1. An electro-hydraulic motor according to claim 20, wherein said thrust-bar is divided, and said electric motor shaft passes through the dividedparts of said thrust-bar.

22. An electro-hydraulic motor according to claim 20, wherein said thrust-bar is divided,V

wherein said rock-shaft is divided, and said electro-motor shaft passes through the divided parts of said thrust-bar and rock-shaft.

WILLIAM J. WOODS. 

